HEAVY METAL ANALYSIS AND GEOCHEMISTRY OF SEDIMENT ON THE GREAT MIAMI RIVER IN HAMILTON, OHIO

This project investigates the nature of heavy metal pollution in sediment of the Great Miami River (GMR) in Hamilton, Ohio. The nature and behavior of heavy metal pollutants in the sediment along the GMR is poorly understood. The hypotheses of the investigation are that pollutant elements are distinguishable within sediment-rich systems that are frequently replenished and remobilized such as the GMR, the majority of the pollutant elements are adsorbed onto clay particles and dispersed diffusely within the sediment, and that these pollutants can be tied to local sources. Thirty samples were collected in early June 2012 from flood deposits and riverbank deposits form the east bank of the GMR north of the High Street bridge and south of the Black street bridge. Sediment samples were analyzed using inductively coupled plasma-mass spectroscopy, inductively coupled plasma-optical emission spectroscopy and scanning electron microscopy.

Bulk chemical analysis indicates that elements of environmental concern (e.g., Zn, Cu, Cr, and Pb) are present in many samples with some variation in concentrations and many of the analyses are above geologic background. Other geochemical parameters are consistent with that expected from glacially derived sediment. SEM indicates some pollutants such as zinc and chromium occur in particulate form but rarely, indicating that the majority of the pollutants occur as adsorbed components on clay minerals. Bulk zinc and copper concentrations show a very strong correlation and the ratio of zinc and copper is consistent with that contained in samples from street sediment collected in Hamilton from a previous study.

This investigation indicates that there are detectable heavy metal pollutants above geologic background in the GMR and these pollutants are largely adsorbed onto sediment. Elemental ratios of some elements such as Cu and Zn are consistent with that in street sediment in Hamilton. The results also provide constraints for comparative analysis of heavy metal pollution in the region and places constraints on environmental management options.